Viral Haemorrhagic Fever

Overview

Viral haemorrhagic fevers (VHFs) refer to a group of epidemic prone diseases that are caused by several distinct families of viruses.

In general, the term "viral haemorrhagic fever" is used to describe a severe multi-system syndrome (multi-system in that multiple organ systems in the body are affected). Characteristically, the overall vascular system is damaged, and the body's ability to regulate itself is weakened. Symptoms are often accompanied by bleeding, though the bleeding is rarely life-threatening. While some types of haemorrhagic fever viruses can cause relatively mild illnesses, many of these viruses cause severe life-threatening diseases.

Viruses causing haemorrhagic fever are initially transmitted to humans when the activities of infected rodents and humans overlap. The viruses carried in rodent reservoirs are transmitted to human contact with urine, faecal matter, saliva, or other body excretions from infected rodents. However, some of these vectors may spread virus to animals, livestock, for example. Humans then become infected when they care for or slaughter the animals.

Specific signs and symptoms vary by the type of VHF, but initial signs and symptoms often include marked fever, fatigue, dizziness, muscle aches, loss of strength, and exhaustion. Patients with severe cases of VHF often show signs of bleeding under the skin, in internal organs, or from body orifices like the mouth, eyes or ears. Some viruses that cause haemorrhagic fever can spread from one person to another.

In the African Region there are many types of VH fevers which have and continue to pose serious health risks: Marburg and Ebola haemorrhagic fevers, Crimean Congo haemorrhagic fever (CCHF), Rift Valley fever (RVF), lassa fever, yellow fever and the newly emergent arenavirus. All cases of acute viral haemorrhagic fever syndrome whether single or in clusters, should be immediately notified without waiting for the causal agent to be identified.